USEFUL FOR INVESTIGATORY PROJECTS

1. RMK SENIOR SECONDARY
SCHOOL
THIRUVERKADU, CHENNAI-77
ACADEMIC YEAR: 2017-‘18
INVESTIGATORY PROJECT IN CHEMISTRY
TOPIC:
TESTING HARDNESS, PRESENCE OF IRON,
FLUORIDE, CHLORIDE IN DRINKING WATER
UNDER THE SUPERVISION OF: SUBMITTED BY:
Mrs.Renusha Chandran K.V.PRADEEP
Reg. No..............................

2. CERTIFICATE
TO WHOMSOEVER IT MAY CONCERN
This is to certify that K.V.PRADEEP is a student of class
XII 'A' of RMK Senior Secondary School for the academic year 2017-’18
under Reg No. ..................................had worked on the project TESTING
HARDNESS, PRESENCE OF IRON, FLUORIDE, CHLORIDE IN DRINKING
WATER under my supervision.
During this period he was found to be sincere and hardworking.
PRINCIPAL Internal Examiner
Submitted during practical examination in Chemistry of the AISSCE held
on.............................at...............................................................................
External Examiner

3. ACKNOWLEDGEMENT
It is customary for me to acknowledgethe contributionsand
suggestions received from various sources.
First of all I would like to thank god almighty for giving me
wisdom and knowledge to showcase my talent.
I am very thankful to our PrincipalMrs. Indira Rangan for giving
me the golden opportunityto do this wonderful project.
I wish to acknowledgethe tremendousamount of help received
from my Chemistry teacher Mrs.Renusha Chandran, without
whose help and encouragement it would not have been
possible for me to complete this project.
I wish to express my gratitude to all non-teaching staff who
helped me to complete my project.
Whatever words I choose cannot sufficiently express my deep
sense of gratitude towards my parents for their constant
understanding,assistance, inspiration and moral support in
completing this project.
I would also like to acknowledge my thanks to my friends for
their valuablesuggestions and timely help.

5. CONTENTS:
 OBJECTIVE
 INTRODUCTION
 THEORY
 APPARATUS
 DETERMINING HARDNESS OF
WATER
 PROCEDURE
 TEST FOR IRON
 TEST FOR CHLORIDE
 TEST FOR FLUORIDE
 RESULT
 CONCLUSION
 BIBLIOGRAPHY

6. OBJECTIVE:
To determine the hardness, presence of iron, fluoride,
chloride depending upon the regional variationin
drinking water and study of causes of presence of these
ions.
INTRODUCTION:
Hardness of water is determined by concentration of
multivalent cations present in water.Hard water contains
Ca2+
, Mg2+
ions.Hardness of water can be removed by
adding sodium carbonate to hard water .Sometimes salts
are dangerous for human health. Therefore, it is
necessary to detect presence of these ions and remove
them to stay on safer side.
TYPES OF HARDNESS IN WATER:
1)Temporary hardness
2)Permanent hardness
TEMPORARYHARDNESS:
Temporary hardness is due to the presence of
biocarbonates of calcium and magnesium. It can be easily
removed by boiling.

7. PERMANENT HARDNESS:
Permanent hardness is due to the presence of chlorides
and sulphates of calcium and magnesium. This type of
hardness cannot be removed by boiling.
SALTS PRESENT IN WATER
Sulphate in groundwater is caused by natural
deposits of magnesium sulphate, calcium sulphate
or sodium sulphate. Concentrations should be below
250 ppm. Higher concentrations are undesirable
because of their laxative effects.
Iron as it exists in natural groundwater is in the
soluble (ferrous) state but, when exposed to oxygen,
is converted into the insoluble (ferric) state with its
characteristic reddish brown or rusty color.
Chlorides in groundwater can be naturally occurring
in deep aquifers or caused by pollution from sea
water, brine, or industrial or domestic wastes.
Chloride concentration above 250 mg/l can produce
a distinct taste in drinking water.
Fluorinated water contains fluoride at a level that is
effective for preventing cavities; this can occur
naturally or by adding fluoride.

10. THEORY:
Hard water : Water with very high mineral
content is called hard water. Hard water is
when water percolates through deposits of
chalk and limestone. We know that limestone
and chalk are made up of calcium and
magnesium carbonates.
Indicator of hardness in water: Hardness in water
indicates an inability to form lather with soap
solution. The effect of various dissolved salts,
containing several different cations and anions, on
the formation on lather, is investigated. Following
example of hard water containing calcium and
magnesium ions, shows formation of insoluble
precipitate.
2 C17H35COO−
Na+
+ Ca2+
→ (C17H35COO)2Ca + 2 Na+
2 C17H35COO−
Na+
+ Mg2+
→(C17H35COO)2Mg + 2Na+

11. APPARATUS:
 Test tubes
 Pipette
 Beakers
 Stop watch
 Corks
 Test tube stand
CHEMICALS REQUIRED:
 Soap solution
 Calcium chloride solution

12.  Sodium sulphate
 Distilled water
 Iron(II)sulphate solution
 Sodium chloride
 Potassium nitrate
 Magnesium sulphate
DETERMINING HARDNESS OF WATER :
 Take eight test tubes and label them as
1,2,3,4,5,6 and 7

13.  Put about 10 drops of the following in
different test tubes:
Test tube 1-distilled or deionised water
Test tube 2-calcium chloride solution
Test tube 3-sodium sulphate solution
Test tube 4-Iron(II) sulphate solution
Test tube 5-Sodium chloride solution
Test tube 6-potassium nitrate solution
Test tube 7-magnesium sulphate
 Take out 50 mL of soap solution in a
small beaker.
 Pipette out about 5 mL soap solution in
each test tube.
 Close the mouth of each test tube with
cork and shake it vigorously.
 Note which tube contains a foamy
lather and which do not.

14.  With the help of stopwatch measure
the time taken for disappearance of foam in
each test tube.
Test
tubes
Solution Lather formed
or not
Time taken for
disappearance of foam
1 Distilled water Yes 35s
2 Calcium chloride No _
3 Sodium sulphate Yes 28s
4 Sodium chloride Yes 31s
5 Potassium
nitrate
Yes 29s
6 Magnesium
sulphate
No _
7 Iron(II) sulphate Yes 32s

15. PROCEDURE:
A. TESTING IRON IN WATER:
 Take 5 mL water in a test tube. Add two
drops of dilute H2SO4.
 Boil the contents and allow it to cool.
 Now, add 2-3 drops of ammonium
sulphocyanide.
OBSERVATION:
Appearance of orange colour indicates the presence
of iron in water.
B. TESTING CHLORIDE IN WATER:
 Take 5 mL water in a test tube. Add 2
drops of concentrated HNO3 in it.
 Boil the contents of the test tube and
allow it to cool.
 Now, add 2-3 drops of AgNO3 solution to
it.

16. OBSERVATION:
Appearance of curdy precipitate indicates the
presence of chloride in water.
C. TESTING FLUORIDE IN WATER:
 Take 5 mL water in a test tube.
 Add water, silver nitrate and dilute
nitric acid to it.
OBSERVATION:
No precipitate indicates presence of fluoride
ion in water.

17. RESULT:Presence of salt contents in different
source of water is detected experimentally.
BIBLIOGRAPHY:
 ENVIRONMENTALJOURNAL ON TOXICOLOGY.
 PUBLICATION BY DEPARTMENT OF PUBLIC HEALTH.
 HANDBOOK OF GROUND WATER DEVELOPMENTBY
ROSCO MOSS.
 SLIDE SHARE